bionic (3) Test::MockModule.3pm.gz
NAME
Test::MockModule - Override subroutines in a module for unit testing
SYNOPSIS
use Module::Name;
use Test::MockModule;
{
my $module = Test::MockModule->new('Module::Name');
$module->mock('subroutine', sub { ... });
Module::Name::subroutine(@args); # mocked
#Same effect, but this will die() if other_subroutine()
#doesn't already exist, which is often desirable.
$module->redefine('other_subroutine', sub { ... });
}
Module::Name::subroutine(@args); # original subroutine
# Working with objects
use Foo;
use Test::MockModule;
{
my $mock = Test::MockModule->new('Foo');
$mock->mock(foo => sub { print "Foo!\n"; });
my $foo = Foo->new();
$foo->foo(); # prints "Foo!\n"
}
DESCRIPTION
"Test::MockModule" lets you temporarily redefine subroutines in other packages for the purposes of unit
testing.
A "Test::MockModule" object is set up to mock subroutines for a given module. The object remembers the
original subroutine so it can be easily restored. This happens automatically when all MockModule objects
for the given module go out of scope, or when you "unmock()" the subroutine.
METHODS
new($package[, %options])
Returns an object that will mock subroutines in the specified $package.
If there is no $VERSION defined in $package, the module will be automatically loaded. You can
override this behaviour by setting the "no_auto" option:
my $mock = Test::MockModule->new('Module::Name', no_auto => 1);
get_package()
Returns the target package name for the mocked subroutines
is_mocked($subroutine)
Returns a boolean value indicating whether or not the subroutine is currently mocked
mock($subroutine => \&coderef)
Temporarily replaces one or more subroutines in the mocked module. A subroutine can be mocked with a
code reference or a scalar. A scalar will be recast as a subroutine that returns the scalar.
The following statements are equivalent:
$module->mock(purge => 'purged');
$module->mock(purge => sub { return 'purged'});
When dealing with references, things behave slightly differently. The following statements are NOT
equivalent:
# Returns the same arrayref each time, with the localtime() at time of mocking
$module->mock(updated => [localtime()]);
# Returns a new arrayref each time, with up-to-date localtime() value
$module->mock(updated => sub { return [localtime()]});
The following statements are in fact equivalent:
my $array_ref = [localtime()]
$module->mock(updated => $array_ref)
$module->mock(updated => sub { return $array_ref });
However, "undef" is a special case. If you mock a subroutine with "undef" it will install an empty
subroutine
$module->mock(purge => undef);
$module->mock(purge => sub { });
rather than a subroutine that returns "undef":
$module->mock(purge => sub { undef });
You can call "mock()" for the same subroutine many times, but when you call "unmock()", the original
subroutine is restored (not the last mocked instance).
MOCKING + EXPORT
If you are trying to mock a subroutine exported from another module, this may not behave as you
initialy would expect, since Test::MockModule is only mocking at the target module, not anything
importing that module. If you mock the local package, or use a fully qualified function name, you
will get the behavior you desire:
use Test::MockModule;
use Test::More;
use POSIX qw/strftime/;
my $posix = Test::MockModule->new("POSIX");
$posix->mock("strftime", "Yesterday");
is strftime("%D", localtime(time)), "Yesterday", "`strftime` was mocked successfully"; # Fails
is POSIX::strftime("%D", localtime(time)), "Yesterday", "`strftime` was mocked successfully"; # Succeeds
my $main = Test::MockModule->new("main", no_auto => 1);
$main->mock("strftime", "today");
is strftime("%D", localtime(time)), "today", "`strftime` was mocked successfully"; # Succeeds
If you are trying to mock a subroutine that was exported into a module that you're trying to test,
rather than mocking the subroutine in its originating module, you can instead mock it in the module
you are testing:
package MyModule;
use POSIX qw/strftime/;
sub minus_twentyfour
{
return strftime("%a, %b %d, %Y", localtime(time - 86400));
}
package main;
use Test::More;
use Test::MockModule;
my $posix = Test::MockModule->new("POSIX");
$posix->mock("strftime", "Yesterday");
is MyModule::minus_twentyfour(), "Yesterday", "`minus-tewntyfour` got mocked"; # fails
my $mymodule = Test::MockModule->new("MyModule", no_auto => 1);
$mymodule->mock("strftime", "Yesterday");
is MyModule::minus_twentyfour(), "Yesterday", "`minus-tewntyfour` got mocked"; # suceeds
redefine($subroutine)
The same behavior as "mock()", but this will preemptively check to be sure that all passed
subroutines actually exist. This is useful to ensure that if a mocked module's interface changes the
test doesn't just keep on testing a code path that no longer behaves consistently with the mocked
behavior.
original($subroutine)
Returns the original (unmocked) subroutine
unmock($subroutine [, ...])
Restores the original $subroutine. You can specify a list of subroutines to "unmock()" in one go.
unmock_all()
Restores all the subroutines in the package that were mocked. This is automatically called when all
"Test::MockObject" objects for the given package go out of scope.
noop($subroutine [, ...])
Given a list of subroutine names, mocks each of them with a no-op subroutine. Handy for mocking
methods you want to ignore!
# Neuter a list of methods in one go
$module->noop('purge', 'updated');
SEE ALSO
Test::MockObject::Extends
Sub::Override
AUTHORS
Current Maintainer: Geoff Franks <gfranks@cpan.org> Original Author: Simon Flack <simonflk _AT_ cpan.org>
COPYRIGHT
Copyright 2004 Simon Flack <simonflk _AT_ cpan.org>. All rights reserved
You may distribute under the terms of either the GNU General Public License or the Artistic License, as
specified in the Perl README file.